Electrical components can be provided as molded injection devices (MID) with desired printed conductors. In contrast to conventional circuit boards made of fiberglass-reinforced plastic or the like, MID components manufactured in this way are three-dimensional (3D) molded parts having an integrated printed conductor layout and possibly further electronic or electromechanical components. The use of MID components of this type, even if the components have only printed conductors and are used to replace conventional wiring inside an electrical or electronic device, saves space, allowing the relevant device to be made smaller. It also lowers the manufacturing costs by reducing the number of assembly and contacting steps. These MID devices have great utility in cell phones, PDAs and notebook applications.
Stamp metal, flexible printed circuit board (FPCB) mounted and two-shot molding methods are three existing technologies to make an MID. However, stamping and FPCB mounted process have limitations in the pattern geometry, and the tooling is expensive. Also, altering of a RF pattern causes high-priced and time-consuming modifications in tooling. 2-shot-molding (two-component injection molding) processes have also been used to produce 3D-MIDs with real three-dimensional structures. For example, an antenna can be formed by subsequent chemical corrosion, chemical surface activation and selective metal coating. This method involves relatively high initial costs and is only economically viable for large production numbers. 2-shot-molding is also not regarded as an environmentally friendly process. All of these three methods are tool-based technologies, which have limited flexibility, long development cycles, difficult prototype, expensive design changes, and limited ability to produce miniaturization. Accordingly, it is becoming increasingly popular to form MIDs using a laser direct structuring (LDS) process. In an LDS process a computer-controlled laser beam travels over the MID to activate the plastic surface at locations where the conductive path is to be situated.
Laser-supported or directed structuring process (LDS) for 3D MIDs simplifies the manufacturing process. Simplifying the miniaturization process, the laser, with possible resolutions of less than 0.1 mm, may produce fine structures and remove material from plastic surfaces with precision and selectivity. For example, the LDS process allows for antenna structures to be directly and cost effectively integrated into a cell phone housing. Further, the LDS process allows for sophisticated mechatronic systems that integrate mechanical and electrical properties for automotive and medical applications. With a laser direct structuring process, it is also possible to obtain small conductive path widths (such as 150 microns or less). In addition, the spacing between the conductive paths can also be small. As a result, MIDs formed from this process can save space and weight in end-use applications. Another advantage of laser direct structuring is its flexibility. If the design of the circuit is to be changed, it is simply a matter of reprogramming the computer that controls the laser.
In a conventional LDS process, a thermoplastic composition can be doped with a metal containing LDS additive such that it can be activated by a laser. The laser beam can then be used to activate the LDS additive forming a micro-rough track on the surface. The metal particles from the LDS additive present on the surface of the micro-rough track can in turn form nuclei for the subsequent metallization. However, due to different chemical plating solutions and conditions used, the plating performance of conventional LDS materials can vary in ways such as plating rate and adhesion of plating layers. In addition, some LDS fillers have a surface pH that may be detrimental to the polymer matrix during processing, resulting in degradation of the polymers. This polymer matrix degradation leads to, for example, decreased ductility for the final composition. The changed ductility, along with and other property changes, may result in substantial, and potentially undesirable, changes in the material's overall properties.
Accordingly, it would be beneficial to provide a LDS blended thermoplastic composition (or LDS compound) having good plating performance while maintaining good mechanical performance. It would also be beneficial to provide a LDS blended thermoplastic composition that is capable of being used in various applications due to the ability of the composition to provide good mechanical performance. It would also be beneficial to provide a thermoplastic composition that is capable of being used in a laser direct structuring process. Accordingly, there remains a need for thermoplastic compositions that prevent or reduce polymer matrix degradation during processing. This and other needs are satisfied by the various aspects of the present disclosure.